A safety switch configured to determine whether a magnetically operated switch which forms part of the safety switch has been welded closed. The safety switch is configured to establish a first magnetic field in the vicinity of the magnetically operated switch. The magnetic field is arranged to move the magnetically operated switch from a first configuration to a second configuration. The safety switch monitors the state of the magnetically operated switch to determine if the magnetically operated switch has been moved by the first magnetic field, thereby determining if the magnetically operated switch has been welded closed.